<?php
//echo "3+4=",sum(x:3,y:4);
//function sum($x,$y){
//    return $x+$y;
//}
declare(strict_types=1);
echo "3+4=",sum(x:3,y:4),"\n";
function sum(int|float|string $x,int|float|string $y):int|float|string{

    if($x>=10||$y>=10)return false;
    return $x+$y;
}
echo "3.6+4.8=",sum(x: 3.4,y: 4.8),"\n";
echo "3.6+4.8=",sum(x: 3.4,y: 4.8), "\n";
var_dump(sum(X:12,y:9));